Project multiple textures during a DynoTopo sculpt?
If you will be using those images as guides to where to sculpt ,use multiple cameras and set up multiple 3d views.
with this setup you could sculpt-draw on a 3d view with the background image and see the changes on another 3d view.  

use multiple cameras , each camera should load an image ,use a low opacity value and set it to display in front of everything.  



you can also keyframe cameras to quickly switch between multiple angles, so that frame 1 is camera 1 and uses an image, frame 2 is another angle from another camera etc..  

I don't think you can use more than one image at a time with this though.